Rifle-barrel



WED JAN. 29. 1920.

Patented Oct 12, 1920.

2 SHEETS-SHEET 1.

N K i \N Qf W J. D. PEDERSEN.

RIFLE BARREL.

UNEZY. [9U- RENEWED IA Patented Oct. 12, 1920.

2 SHEETSSHEET 2.

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.... h m u m m M M M m p ,w A n M w AN m w .w E m w gmv i w 1 w k u Q n w kfi z PATENT OFFICE.

JOHN D. PEDERS'EN, OF JACKSON, WYOMING.

RIFLE-BARREL.

Application filed June 27, 1917, Serial To all whom, it may concern:

Be it known that I, JOHN D. PEDERSEN, a citizen of the United States, residin in Jackson, in the county of Lincoln and l tate of W oming, have invented certain new and usefu Improvements in Rifle-Barrels, of which the following is a specification.

A principal object of this invention is to furnish an improved barrel especially adapted for use in rifled shoulder arms. further object is to provide means whereby the work of finall shaping the projectile to conform to an engage with the rifling ribs and in the rifling grooves, will be accomplished by and in successive stages or periods, so that said work will be carried out in the rearward portion of the barrel in a modulated and progressive manner. Further advantages and objects are pointed out and explained in the course of the following description.

In the drawings accompanyin and forming a part of this specification, iigure 1 is a side view, principally in section, of a rifle barrel made in accordance with my present improvements, and of composite construction; and, Fig. 1 is a similar view drawn on a different scale, of the barrel when made of integral construction.

Fig. 2 is an end view, left-hand in Fig. 1.

Figs. 3 and 4 are cross sections in lines X and K, respectively, of Fig. 1, and Figs. 3" and 4 are views supplemental thereto as hereinafter explained.

Figs. 5, 6 and 7 are enlarged detail views which are especially arranged for illustrating certain features of the rifling, as hereinafter more fully explained.

Figs. 5 and 5 are views analogous to a portion of Fig. 5, for illustrating certain variations in the form or arrangement of successive portions of the rifiing ribs.

Fig-6 is a view similar to Fig. 6, for illuss trating a further modification of, or variation in, the rifling of the barrel.

Fi 8 is a diagrammatic view for approximate y representing certain features of my improved rifle barrel with relation to the usual gas-pressure curve or diagram.

Similar reference characters designate like parts in all the views.

Referrin to the drawin B indicates a as seen from the 'rifie barre of ordinary c aracter; it may have, in practice, any suitable external size and form, and in Fig. 1, also in Fig. 1, a

Specification of Letters Patent.

Patented Oct. 12, 1920.

No. 177,252. Renewed January 29, 1920. Serial No. 854.883.

lar e portion of the length is broken away, an only the rearward portion of the barrel is fully shown. In practice, the barrel B,- which, for the purposes of this description, I designate as the main barrel,may have such size, length and proportions as may be suitable for the particular firearm of which this barrel is to form a part, and I have herein represented in an approximate manner such a barrel of the class common to military shoulder arms. These barrels are now generally made with bore,as E, Fig. 1,having a diameter of about three-tenths of one inch, but in the present drawings, Figs. 1 to 5", are drawn on a somewhat lar r scale.

t the rearward end thereof, the barrel B (Figs. 1, 2) is shown at 10, reduced in size and threaded, by way of showing one ordinary way,- which may be adopted when desired,-of fitting the barrel to be removably fixed in the usual receiver, or frame, (not shown) of a firearm. in a well-known manner. Also, said main barrel B is shown as bein bored out, (to the lines 12, 12, Fig. 1), to orm the usual cartrid e chamber, as 12, for the shell, or pow er-case, (not shown) of a high-power cartridge having a long-range projectile. Into said chamber 12, a secondary barrel, D, is closely fitted, thus forming a complete barrel having a composite construction. It should be understood, however, that in some instances, if desired, the portion D may be made integral with the portion B; in this case, of course, the barrel B will have no chamber 12 available for use on the removal of the member D. This integral form of the complete barrel is illustrated in Figs. 1 and 8, and is hereinafter more fully explained.

In the composite form of the barrel shown in Figs. 1, 2, 3, the member D is extended rearwardly of the member B, and is there shown enlarged, as at 14, and provided with a cartridge chamber 15 the forward portion of which is an un-rified projectile seat; this chamber should, be suitable for the cartridges which, in any given instance, are to be used in the composite barrel. Said chamber 15, in some instances if desired, may be of the same size and proportions as the chamber 12, but said composite form of the barrel is more especially intended for use with ammunition of two kinds, viz., for high-power, long-range cartridges when the member D is removed, and for a lower power and shorter range cartridge, when said member I) is in place.

Thus in the complete barrel, this has a continuous bore which in a short length thereof, and adjacent to the chamber 15 in the rear end thereof, (as in the zone N from line V to line V, Figs. 1, 1', 8), is provided with relatively small rifiing ribs for initially grooving a projectile, and which forward of said small ribs; and forward of said zone N of the initial projectile-grooving action. is provided with rifling ribs arranged for increasing the initial grooving of the projectile. Thus the complete barrel-rifling operates to groove the projectile by a twostage method or process, whereby the initially-grooved projectile is subsequentl regrooved or rifled by an operation whic begins after a time-interval that is subsequent to the completion of said first operation. A further feature is that said zone N of initial grooving, is extended forwardly from said chamber 15 to a length or point forward of the position when the gases normally will have reached their maximum pressure, so that the projectile will pass from the relatively small to the larger rifling ribs at a time when the gas-pressure is beginning to decrease; during this period,or time-interval,it is believed that the velocity of the projectile will be most rapidly increasing. not in ratio or percentage of speed, but as regards the distance traveled through in a given unit of time; this kind of increase of velocity must, of course, disap ar at or somewhat before the projectile eaves the muzzle of the barrel.

The main barrel B is shown provided with rifling ribs, 5, (preferably of a usual helical form), which are indicated of a conventional form, in the sections, in Fi 4 and 5. Similarly, the secondary or auxiliary barrelportion D, is shown rovided with the smaller rifling ribs 7, siown in section in l igs. 2, 3, and 5. These two sets of ribs are intended to be of similar number and arrangement, (Fig. 5), and thus form a continuation, the one of the other. This relation of the ribs is illustrated (but without the curvature thereof) in a lan view, Fig. 6, and in a side view of the ribs in Fig. 7; in these views a further feature is shown, in that, within the zone 8, (see Figs. 1, 1, and 6), the portion 5 of the ribs 5 is reduced to a tapering form, thus avoiding a sudden increase in size or a marked obstruction at the forward end of the rib 7. Said additional feature, however, of the tapered parts 5', may not be re uired in all cases, and it is not essential to t e principal features of mypresent invention.

For convenience of illustration, and to aid clearness in the drawing, the depth of the rifling grooves (that is, the height of the rifiing ribs) has been shown somewhat exaggerated, and the ribs, as 7, of the initial ri mg are shown of a size relativel lar as compared with the ribs, as 5, of t e final or main rifling. (Compare Figs. 5, 5", 5", 6, 7). The relative efl'ects of the ribs ugon a pro ectile are approximately shown in i 3' and 4, whic corres nd with the inner outlines of the bore of t e barrel, in Figs. 3 and 4, respectively. Thus Fig. 3' shows a cross-section of a pro'ectile, J as if initially grooved,as at 7, y the ribs 7, Fi 3. Similarl Fig. 4 shows said projecti e as having t ie rooves 7 enlarged to the form 5 by the ri is, 5, of the barrel B in Fig. 4. In the form of barrel shown in ig. 1, said groove enlargement will take place when the projectile passes the line 9, or within the zone 8.

The slight resistance offered by the relatively small ribs 7 to the initial forward movement of the projectile, permits this movement to begin at a time (at a moment) when the gas-pressure is still comparatively low so that the space behind the projectile will be materially enlarged during a very early stage of the combustion. Consequently, during that initial forward movement, the projectile will have not only a low velocity, but also a low degree of acceleration, so that a minimum amount of power will be consumed during that moment in inauguratin the rotation of the projectile, and there y permit a more rapid acceleration of the forward movement under a given and relatively low gas pressure. Thus the rapidly increasing forward movement while the projectile is subjected to the low rib-resistance, tends to correspondingly increase the gas-space before the gas-pressure can rise to its maximum. As a result of this action, the curve by which the gas-pressure is usually represented in a well-known diagrammatic manner, will be materially modified in a way to show a delay,as compared with the hitherto accepted practice,--of the moment when the gas will attain maximum pressure; this normally operates to reduce the maximum strain upon the barrel due to the burning therein of a given quantity of powder behind a projectile of a given weight, and also,-w1th a given limit of that strain,provides for burning a relatively larger quantity of owder behind a pro'ectile of a given welght. These features an advantages appertain, of course, to the complete barrel whether this is of integral or composite construction.

By reason of the modulation, as above explained, of the forces and pressures, the torsional strain on the initial rifiing (and especially during the first one or two inches of said forward movement of the projectile), will be less than normally occurring with the usual style of riflin which is uniform throughout the length 0 the barrel. llem-e I my present improvements are especially applicable to rifled firearms having barrels of composite construction, and in which a main barrel is adapted for using high-power cartridges and is also, for some uses, provided with an adapter, the bore of which forms a rearward extension of the bore of the main barrel; one arm of this class,a military shoulder-arm,-is described in m application filed April 28th, 1917, Serial 0. 165,171, to which reference ma be had.

In practice, by the time when the projectile has reached the forward end of the initial ribs 7 and thus come to the larger rifling ribs 5, the projectile has acquired such a velocity and momentum that it will take the rifling of the main barrel without difficulty, and will do this before the period of the most rapid acceleration. As a result, therefore, of the said features and mode of action, when the barrel is provided with the relatively thin adapter-extension or supplemental barrel, as D, this is so far protected and relieved of the otherwise heavy strain, as to be reliable and effective under the severe conditions of continued service. Thus, also, I avoid the highly destructive action upon the projectile, which occurs when the bore of the adapter-barrel is a smooth-bore (not herein shown) that construction (as I have found by extended trials) allows the projectile to initially advance too rapidly, so that on striking the rifling ribs, as at 9, of the main barrel,-and being then without rotation,the projectile is impaired in quality and in trajectory, and often will be so cut and deformed as to be practically destroyed before leavin the .barrel.

For more illy indicating the foregoing explanations, I have shown in Fig. 8, a gaspressure diagram, M, drawn in a conventional manner with the base-line m thereof along side of the rifle barrel B, this being substantially the same as the composite form of barrel, except that it is shown as if made integral. In this diagram, the pressure curve 3 is of a form re resenting results such as commonly obtaine in military rifles. Beginning at the point, 3 of initial pressure, the line 3 then rises rapidly to the point, as 3*, of a maximum pressure which is normal to the barrel. By this term, of course, is meant that the line, as 3, to which the projectile will have no forward, when the pro'ectile is prope ed by a charge normall use in the ammunition for the use of whic the cartridge chamber 15 is constructed. In practice, this portion of forward movement of the projectile will extend forwardlyat least as far as a line of maximum pressure,- as 3, Fig. 8,-and preferably should extend at least to said line when the barrel is used for the largest powder charges proper therefor. Thus the small-ribs zone, as N, may usually have a length which is somewhat larger ribs,

greater than that of the rising-pressure zone so that,-as herein ex lained,the increased resistance due to t e projectile encountering the larger ribs 5, will be delayed, and so will not occur until after the gaspressure has begun to reduce; this feature, or point of action, is indicated in an evident manner by the descending part 3 of said pressure curve 3. In ractice, the minimum length of the zone 1\ may be regarded as equal to two and one-half times the diameter of the bore E, while a normal and preferable range thereof may be between four and ten diameters or calibers, according to size of bore, the twist of the rifiing, and the character and power of the cartridges to be used; all these matters or factors are readily ascertainable by trial in any particular instance.

The position where the smaller ribs 7 meet the larger ribs 5, may be designated as the groove-enlarging zone; in Figs. 1, 1", and 6, this zone, 8, has a considerable length, so that the fully formed ribs 7 and 5 may be connected by an intervening length, as 5', constituting a groove-enlarging means. Also, said portion 5' may be regarded as constituting a rearward part of one of said as 5, which is tapering and is thus reduced in size to correspond with one of said smaller ribs, as 7, and thereby form a means for enlarging the grooving of the projectile in the gradualmanner normally due to the action of a wedge. The form and character of the groove enlargement may vary in different instances; this will be seen by a comparison of Figs. 5, 5" and 5". In Fig. 5 the initially-grooving rib 7 is of the same width, but of less height, than rib 5 and operates to increase the depth of the grooving; in Fig. 5", the rib 7 is of the same height but of less width than rib 5, and operates to increase the width of the grooving; in Fig. 5, the rib 5 is both higher and wider than the rib 7, and hence operates to increase both the depth and width of the rooving. In each said instance, however, it is evident that the barrel, forward of said small rifling ribs, as 7, is provided with larger rifli'ng ribs that are in osition for inlcreased the initial grooving o the projecti e.

In Figs. 1 6 and 7,-also in Fi 1,-the ribs 7 are indicated as extending orward to closely join or contact with the larger ribs 5, but it should be understood that in some instances if desired, a s ace, or un-ribbed zone, as 8', Fig. 6', may located between said ribs. In this case however, the ribs'7 and 5 not only form a continuous" rifling rib for the com lete barrel, sinoe'both said ribs,-as shown 11-. Fi 6,-are in alinement with the same meri an line, S, but said larger ribs 5, similarl and 'equall as in Fig. 6, are in position 'orward of said small ribs, for increasing the initial grooving of the projectile. By its motion and momentum acquired in the zone N, the pro'ectile will readily pass from the ribs 7 and over said zone 8 and continue along the rib 5, in the required manner. The special features here described in connection with Fig. 6", have the advantage of permitting the extreme forward part,-as the narrow zone 8',to be without ribs, thus tending to reduce the strain at and on the forward part or point-portion of the insertible part D which is contiguous to the line 9.

Having thus described my invention, I claim:

1. A rifle barrel for the two-stage grooving of a projectile, said barrel having in the rear end thereof a cartridge chamber with an unrifled projectile seat, and having a continuous bore which in a zone thereof contiguous to said projectile-seat is provided with relatively small projectile-grooving rifling ribs for initially-grooving a projew tile, and which forward of said small ribs is provided with larger rifling ribs that are in position for increasing the initial grooving of the projectile, said bore being of a uniform diameter from said chamber to a point forward of the rearward end of said larger riflin ribs.

2. A rifle arrel for the two-stage grooving of a projectile, said barrel having in the rear end thereof a cartridge chamber with an unrifled pro'ectile seat, and having a continuous bore w ich adjacent to said projectile-seat is provided with relatively small projectile-grooving riflin ribg for initiallygrooving aprojectile, an which forward of said small ribs is provided with riflin ribs having roove-wi ending inclines emf of a size an arrangement or increasing the depth of the initial grooving of the projectile, said bore being of a uniform diameter from said chamber to a point forward of the rearward end of said lar r rifling ribs.

A rifle barrel for tfi: two-stage grooving of a projectile, said barrel having in the rear end thereof a cartridge chamber with an unrifled projectile seat, and havinga continuous bore which adjacent to said projectile-seat is provided with relatively small projectile-grooving riflin ribs for initiallygrooving a projectile, and which forward of said small ri is provided with larger rifling ribs havin groove-widening inclines and of a size amf arrangement for increasing the width of the initial groovinfg of the projectile, said bore being of a uni orm diameter from said chamber to a point forward of the rearward end of said larger rifling ribs.

4. A rifle barrel for the two-stage grooving of a projectile, said barrel having in the rear end thereof a cartridge chamber with an unrifled projectile seat, and having a contiguous to said tinuous bore which adjacent to said projec tile-seat is provided with relatively small projectile-grooving rifling ribs for initiallygrooving a projectile, and which forward of said small ribs is rovided with rifling ribs having groove-wi ening inclines and of a size and arrangement for increasin the depth and also the width of the initial grooving of the projectile, said bore being of a uniform diameter from said chamber to a mint forward of the rearward end of said arger rifling ribs.

5. A rifle barrel for the two-stage grooving of a projectile, said barrel having in the rear end thereof a cartridge chamber with an unrifled projectile seat, and having a continuous bore which in a zone thereof conprojectile-scat is provided with relatively small projectilee-grooving rifling ribs for initially grooving a projectile, and which forward of said small ribs is provided with larger rifling ribs that are in position for increasing the width of the initial grooving-of the )rojectile, said bore being of a uniform iameter from said chamber to a point forward of the rearward end of said larger rifling ribs, said larger rifling ribs each having a rearward portion thereof reduced in size and shaped to form a groove-enlarging means.

6. A rifle barrel for the two-stage grooving of a projectile, said barrel having in the rear end thereof a cartridge chamber with an unrifled projectile seat, and having a continuous bore which in a zone thereof contiguous to said projectile-seat is provided with relatively small projectile-grooving rifling ribs for initiall grooving a projectile, and which forwar of said small ribs is provided with larger rifling ribs that are in position for increasing the width of the initial grooving of the projectile, said bore being of a umform diameter from said chamber to a point forward of the rearward end of said larger rifling ribs, said larger rifling ribs each having a tapcrln and groove-en larging portion which at t 1e rearward end thereof is reduced in size to correspond with said small rifling ribs.

7. A rifle barrel for the two-stage grooving of a projectile, said barrel having in the rear end thereof a cartridge chamber with an unrifled pro'ectile seat, and having a continuous bore w ich adjacent to said projectile-seat is provided with a series of relatively small projectile-grooving rifling ribs for initially grooving a projectile, said bore being of a uniform diameter from said chamber to a point forward of the rearward end of said larger rifling ribs. and which forward of said small ribs is provided with a corresponding series of relatively larger parallel-sided rifling ribs that are continuations, res actively, of said smaller ribs.

8. A ri e barrel for the two-stage groovjectile,

ing of a projectile, said barrel having in the rear end thereof a cartridge chamber with an unrifled projectile seat, and having a continuous bore which in a zone thereof adjacent to said projectile-seat is provided with a series of relatively small projectile-grooving rifling ribs for initially grooving a proand which forward of said smallribs zone is provided with a corresponding series of relatively larger parallel-sided rifiing ribs that are oontinuations, respectively, of said smaller ribs, said barrel also having said small-ribs zone of a length extending forwardly of the line of maximum gas-pressure which is normal to the barrel.

9. A rifle barrel for the two-stage grooving of a projectile, said barrel havlng in the rear end thereof a cartridge chamber with an unrifled projectile seat, and. having a continuous bore which in a zone thereof adjacent to said projectile-seat is provided with a series of relatively small projertilegroovmg rifling ribs for initially grooving a projectile, and which forward of said smallribs zone is provided with a corresponding series of relatively larger parallel-sided rifling ribs for more deeply grooving the projectile, said barrel also having said small-ribs zone extending forwardly at least as far as a line of maximum gas-pressure which is normal to the barrel.

JOHN D. PEDERSEN.

Witnesses:

L. E. Wn'rMoRE, E. C. GILBERT. 

